Molecular cloning and characterization of the trichome specificchrysanthemyl diphosphate/chrysanthemol synthase promoter fromTanacetum cinerariifolium

Natural pyrethrins accumulate to high concentrations in the flower achenes of pyrethrum (Tanacetumcinerariifolium). They are extracted from dried flowers and widely used as a natural pesticide. Chrysanthe-mol synthase (CHS) is the first key enzyme in the biosynthesis of pyrethrins. In this work, a 1128 bp TcCHSpromoter fragment was cloned from pyrethrum genomic DNA. The sequence contained cis-elementspredicted to be responsive to different hormones, light, and environmental stresses. To characterizethe promoter it was fused to the reporter genes green fluorescent protein (GFP) and -glucuronidase(GUS), and respectively transformed into florist’s chrysanthemum (Chrysanthemum morifolium ‘1581’)and tobacco (Nicotiana tabacum). GFP fluorescence in florist’s chrysanthemum ‘1581’and GUS staining oftobacco showed that the TcCHS promoter was exclusively expressed in the glandular secretory trichomes(GSTs) of both plant species. The findings will support research on factors influencing the accumulationof pyrethrins, and can be used for trichome-specific metabolic engineering of plants to ensure minimaladverse effects on plant growth and development.